Space heating appliance

Abstract

Radiant tube space heating appliance includes a burner assembly (12), air flow therethrough being induced by a fan (14) by way of a restricted air inlet orifice (34) communicating with a stabilizing chamber (32) leading to the burner head (26) for smoothing and silencing the air flow; the burner head including a flame stabilizing matrix (40), conveniently formed from windings of flat and corrugated stainless strips (42,43) which define through apertures of substantial axial length. The appliance may further include a turbulator insert (50) in the radiant tube formed as a corrugated strip (52) of stainless steel or similar material which is twisted to form a helix.

We claim: 
     
       1. A heater assembly comprising a radiant tube for carrying a stream of hot gases to provide space heating by radiation from the tube; gas flow inducing means at a downstream part of said tube for inducing the flow of said stream of gases along said tube; burner means within a combustion chamber having spaced walls, said combustion chamber having an outlet in one of said walls and an inlet in another of said walls, said inlet being in communication with said tube upstream from said flow inducing means; air feed means upstream from said burner means for providing combustion air to said inlet of said combustion chamber, said air feed means comprising a stabilization chamber having a restricted inlet orifice, said stabilization chamber having a capacity sufficient to smooth and slow to a lower velocity air admitted to said stabilization chamber via said inlet orifice thereby silencing turbulence resulting from the passage of air through said inlet orifice; and inlet sleeve means in communication with said stabilization chamber remote from said inlet orifice and extending into said combustion chamber in coaxial relationship with said burner means for directing said combustion air evenly along and in encircling relationship to said burner means in a direction axially thereof in a smooth path with little restriction or abrupt changes of direction, said burner means inducing a flame stabilising matrix at its mouth defining a plurality of through passages of substantial length for stabilising combustion at the downstream end of the burner means while resisting burning back into the burner means. 
     
     
       2. An assembly according to claim 1 including a flow modifying insert within said tube, said insert comprising a strip of sheet material twisted about a longitudinal axis to form a helix. 
     
     
       3. An assembly according to claim 2 wherein said strip is traversely corrugated. 
     
     
       4. An assembly according to claim 3 wherein the corrugations are formed by passing the strip through a pair of meshing toothed rollers to crim it. 
     
     
       5. An assembly according to claim 2 wherein said material is 0.3 mm gauge stainless steel. 
     
     
       6. A assembly according to claim 2 characterised in that the twisting is effected before the strip is inserted into the tube. 
     
     
       7. A assembly according to claim 2 characterised in that the twisting is effected while the strip is being fed into the tube. 
     
     
       8. An assembly as in claim 1 characterised in that the flame stabilising matrix comprises windings of strip material arranged to define said plurality of through passages. 
     
     
       9. An assembly as in claim 8 characterised in that said windings are of alternate layers of corrugated strip material and flat strip material. 
     
     
       10. An assembly as in claim 8 characterised in that said strip material is stainless steel. 
     
     
       11. An assembly according to claim 1 wherein said sleeve means has an outer end located within said combustion chamber and an inner end which smoothly merges with said another wall of said combustion chamber. 
     
     
       12. An assembly according to claim 1 wherein said stabilising chamber is L-shaped and has a smoothly curved wall along one side of said stabilization chamber, said inlet orifice and said sleeve means being spaced from and substantially parallel to one another.